As a market of portable electronic apparatuses such as mobile phones, camcorders, and notebook computers is expanding and diversifying, demands for rechargeable secondary batteries for supplying power are also expanding. Down-sizing, weight lightening, performance improvement, and multi functionalizing of portable electronic apparatuses require continuous improvement of an energy storage density of a secondary battery which is used as a power source. Therefore, as a result of many years of studies for satisfying the demands, a lithium ion secondary battery which employs a carbon cathode which is capable of reversible intercalation and deintercalation of lithium and an anode material which is capable of reversible intercalation and deintercalation of lithium appears.
As compared with an aqueous system secondary battery of the related art such as nickel-cadmium and nickel hydrogen, the lithium ion secondary battery has a higher energy density per unit weight and a longer charging/discharging life. Therefore, the lithium ion secondary battery is rapidly replacing the existing batteries as a new energy source for the portable electronic devices. However, even though in accordance with rapid development and diversification of the portable electronic apparatuses, demands for selecting a battery having a higher energy density and various specifications are rapidly increasing, the existing lithium ion secondary battery does not satisfy the above-mentioned demands.
Specifically, rapid thickness reducing and down-sizing of the electronic apparatus rapidly expand the demands for a thin lithium ion secondary battery. However, when an assembling method of a cylindrical or rectangular lithium ion secondary battery of the related art is directly employed, the energy density per volume is too much lowered due to the thin thickness. Therefore, it is determined that the development of a thin lithium ion secondary battery having a high energy density per volume is essential to accomplish down-sizing, weight lightening, and thickness reducing of various portable electronic apparatuses.
Therefore, in order to solve the above-mentioned problems, the applicant developed a secondary battery using a pocketing electrode body and a lithium ion secondary battery using a pocketing electrode body and a manufacturing technique are disclosed in Korean Registered Patent Nos. 10-1168651 and 10-0337707 which are filed and registered by the applicant.
The related-art patents solve some of the above-mentioned problems. However, there is a problem in that in the lithium ion secondary battery using a pocketing electrode body, a flat or pouch-shaped external case such as a coin type or a button type is generally manufactured as a typical shape, so that when a shape of the electronic apparatus in which the secondary battery is used is changed, the secondary battery having a typical shape cannot be used.
Recently, since a design of the electronic apparatus becomes one of major selection criteria of consumers, a lot of curved electronic apparatuses having a stylish and beautiful shape have been released.
However, when the secondary battery of the related art is accommodated in the curved electronic apparatus or an electronic apparatus in which an uneven space is inevitably formed due to electronic parts, there may be a remaining space in the secondary battery accommodating space in the electronic apparatus which is not filled by the secondary battery.
Further, when a protrusion is formed in a case where the secondary battery is received, a space where the secondary battery is accommodated is reduced due to the protrusion so that the accommodating space is not appropriately utilized.
Therefore, the secondary battery of the related art cannot efficiently utilize the remaining space of the accommodating space so that the secondary battery of the related art is not satisfactorily applied to a curved electronic apparatus or an electronic apparatus having an uneven space or a space formed by a protrusion in terms of a battery capacity or a usage time.
Therefore, the applicant suggests the present invention which may increase the battery capacity or a usage time of a secondary battery by efficiently utilizing a remaining space of the accommodating space and provide a shape and structure for reducing restrictions on a shape of the electronic apparatus in which the secondary battery is used.